Circular surgical stapling device including buttress material

ABSTRACT

A buttress material and mounting structure assembly is provided for use with a circular surgical stapling device. The assembly comprises a ring-like mounting structure sized to have an outer diameter that frictionally engages a radial inner surface of a staple cartridge assembly, wherein the mounting structure is disposed within the radial inner surface of the staple cartridge assembly; an annular buttress material overlaying a tissue facing surface of the staple cartridge assembly, the annular buttress material defining an outer radial terminal edge extending radially beyond a pair of annular arrays of staple receiving slots, and a radial inner terminal edge extending across the mounting structure; and at least one suture securing the buttress material to the mounting structure.

CROSS-REFERENCE TO RELATED APPLICATION

The present application is a Continuation Application which claims that benefit of and priority to U.S. patent application Ser. No. 15/590,332, filed on May 9, 2017, which is a Continuation Application which claims that benefit of and priority to U.S. patent application Ser. No. 14/064,280, filed on Oct. 28, 2013 (now U.S. Pat. No. 9,655,620), the entire content of which is incorporated herein by reference.

BACKGROUND Technical Field

The present disclosure relates to surgical stapling devices and buttress materials for use with said surgical stapling device and, more particularly, to structures and methods for attaching a buttress material to a surgical stapling device for use in anastomosis procedures.

Background of Related Art

Staples have traditionally been used to replace suturing when joining or anastomosing various body structures such as, for example, the bowel or bronchus. The surgical stapling devices employed to apply these staples are generally designed to simultaneously cut and seal an extended segment of tissue in a patient, thus vastly reducing the time and risks of such procedures.

Linear or annular surgical stapling devices are employed by surgeons to sequentially or simultaneously apply one or more linear rows of surgical fasteners, e.g., staples or two-part fasteners, to body tissue for the purpose of joining segments of body tissue together and/or for the creation of anastomoses. Linear surgical stapling devices generally include a pair of jaws or finger-like structures between which body tissue to be joined is placed. When the surgical stapling device is actuated and/or “fired”, firing bars move longitudinally and contact staple drive members in one of the jaws, and surgical staples are pushed through the body tissue and into/against an anvil in the opposite jaw thereby crimping the staples closed. A knife blade may be provided to cut between the rows/lines of staples. Examples of such surgical stapling devices are described in U.S. Pat. Nos. 4,354,628, 5,014,899 and 5,040,715, the entirety of each of which is incorporated herein by reference.

Annular surgical stapling devices generally include an annular staple cartridge assembly including a plurality of annular rows of staples, typically two, an anvil assembly operatively associated with the annular cartridge assembly, and an annular blade disposed internal of the rows of staples. Examples of such annular surgical stapling devices are described in U.S. Pat. Nos. 5,799,857 and 5,915,616 to Robertson et al., the entirety of each of which is incorporated herein by reference.

In general, an end-to-end anastomosis stapler typically places an array of staples into the approximated sections of a patient's bowels or other tubular organs. The resulting anastomosis contains an inverted section of bowel which contains numerous “B” shaped staples to maintain a secure connection between the approximated sections of bowel.

For most procedures, the use of bare staples, with the staples in direct contact with the patient's tissue, is generally acceptable. The integrity of the tissue will normally serve to prevent the staples from tearing out of the tissue and compromising the sealing before healing has occurred. However, in some surgical operations, surgical supports, e.g., meshes or buttress materials, are employed by surgeons in combination with linear stapling devices to bridge, repair and/or reinforce tissue defects within a patient, especially those occurring in the abdominal wall, chest wall, diaphragm, and other musculo-aponeurotic areas of the body. Examples of suitable surgical supports are disclosed in U.S. Pat. Nos. 3,054,406, 3,124,136, 4,347,847, 4,655,221, 4,838,884, 5,002,551, and 7,942,890, the entirety of each of which is incorporated herein by reference.

When the staples are applied in surgical procedures utilizing surgical supports (i.e., reinforcing material), the legs of the staple typically pass from the cartridge jaw through a layer of the surgical support, and through the patient's tissue before encountering the anvil jaw.

While the surgical supports described above are used in conjunction with linear surgical stapling devices, the need exists for annular support structures for use in conjunction with annular or circular surgical stapling devices, for example, an end-to-end anastomosis stapler such as a Model “EEA™” instrument available from COVIDIEN LP, New Haven, Conn. and disclosed in U.S. Pat. No. 5,392,979 to Green et al.

One possible side effect of any end-to-end bowel anastomosis is its tendency to undergo stenosis over time, which can decrease the diameter of the lumen over time. Accordingly, the need exists for an annular surgical structure which operates in conjunction with any end-to-end, annular, or circular anastomosis or stapling device and assists in keeping open the lumen of the anastomosed bowel or other tubular organ over time.

A need also exists for an annular support structure which operates in conjunction with any end-to-end, annular or circular stapling device to reduce the trauma suffered by the patient, reduce the instances of leakage, reduce the instances of bleeding, and create a relatively strong bond between adjacent body tissues.

SUMMARY

The present disclosure relates to structures and methods for attaching a buttress material to a surgical stapling device for use in anastomosis procedures.

According to one aspect of the present disclosure, a surgical stapling device for joining tissue portions is provided and includes a handle assembly; a tubular body portion supported on a distal end of the handle assembly, the tubular body portion having a staple cartridge assembly containing a plurality of surgical staples within a pair of annular arrays of staple receiving slots formed in a tissue facing surface thereof, the staple cartridge assembly defining a radial inner surface and a radial outer surface; and an anvil assembly at a distal end of the surgical stapling device, the anvil assembly having a shaft for removably connecting the anvil assembly to the tubular body portion, the anvil assembly and tubular body portion being juxtaposed with respect to one another along the shaft and arranged so as to be approximated with respect to one another.

The surgical stapling device further includes a ring-like mounting structure sized to have an outer diameter that frictionally engages the radial inner surface of the staple cartridge assembly, wherein the mounting structure is disposed within the radial inner surface of the staple cartridge assembly; an annular buttress material overlaying the tissue facing surface of the staple cartridge assembly, the annular buttress material defining an outer radial terminal edge extending radially beyond the pair of annular arrays of staple receiving slots, and a radial inner terminal edge extending across the mounting structure; and at least one suture securing the buttress material to the mounting structure.

According to another aspect of the present disclosure, a buttress material and mounting structure assembly is provided for use with a circular surgical stapling device including a staple cartridge assembly containing a plurality of surgical staples within a pair of annular arrays of staple receiving slots formed in a tissue facing surface thereof, the staple cartridge assembly defining a radial inner surface and a radial outer surface. The buttress material and mounting structure assembly includes a ring-like mounting structure sized to have an outer diameter that frictionally engages the radial inner surface of the staple cartridge assembly, wherein the mounting structure is disposed within the radial inner surface of the staple cartridge assembly; an annular buttress material overlaying the tissue facing surface of the staple cartridge assembly, the annular buttress material defining an outer radial terminal edge extending radially beyond the pair of annular arrays of staple receiving slots, and a radial inner terminal edge extending across the mounting structure; and at least one suture securing the buttress material to the mounting structure.

The mounting structure may be fabricated from an elastomeric material.

Each suture may extend through the buttress material and through the mounting structure.

Each suture may include a first end, a second end, and a bridge portion interconnecting the first end and the second end, wherein the first end and the second end of each suture extends through the buttress material and through the mounting structure.

The buttress material may define an annular inner attachment portion; an annular middle staple engaging portion, disposed radially outward of the inner portion; and an annular outer portion, disposed radially outward of the middle portion.

Each suture may extend through the annular inner attachment portion of the buttress material. The first end and the second end of each suture may extend through the buttress material and through the mounting structure.

The bridge portion of each suture may extend in a direction transverse to a central axis of the buttress material.

A proximal and an outer corner of the mounting structure may be chamfered.

According to yet another aspect of the present disclosure, a method is provided of using a buttress material and mounting structure assembly for use with a circular surgical stapling device including a staple cartridge assembly containing a plurality of surgical staples within a pair of annular arrays of staple receiving slots formed in a tissue facing surface thereof, the staple cartridge assembly defining a radial inner surface and a radial outer surface.

The method includes the steps of providing a buttress material and mounting structure assembly including a ring-like mounting structure sized to have an outer diameter that frictionally engages the radial inner surface of the staple cartridge assembly; an annular buttress material overlaying the tissue facing surface of the staple cartridge assembly, the annular buttress material defining an outer radial terminal edge and a radial inner terminal edge; and at least one suture securing the buttress material to the mounting structure.

The method further includes the step of positioning the buttress material and mounting structure assembly at least partially within the cartridge assembly of the surgical stapling device such that the mounting structure is disposed within the radial inner surface of the staple cartridge assembly; and the outer radial terminal edge of the annular buttress material extends radially beyond the pair of annular arrays of staple receiving slots, and the radial inner terminal edge of the annular buttress material extends across the mounting structure.

The method further includes the steps of receiving body tissue between the anvil assembly and the cartridge assembly; grasping the body tissue between the anvil assembly and the cartridge assembly; and firing the surgical stapling device to drive a plurality of staples from the staple cartridge assembly through the buttress material and the body tissue; and sever the buttress material radially outward of the at least one suture.

The mounting structure may be fabricated from an elastomeric material, and the step of positioning the buttress material and mounting structure assembly at least partially within the cartridge assembly of the surgical stapling device may include the elastomeric mounting structure radially engaging the inner surface of the staple cartridge assembly in a press-fit manner.

Any of the above aspects of the present disclosure described may be combined with any other aspect of the present disclosure without departing from the scope of the present disclosure.

BRIEF DESCRIPTION OF DRAWINGS

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the disclosure and, together with a general description of the disclosure given above and the detailed description of the embodiments given below, serve to explain the principles of the disclosure, wherein:

FIG. 1 is a perspective view of an exemplary annular surgical stapling device according to the present disclosure;

FIG. 2 is a perspective view, with parts separated, of a head portion of the surgical stapling device of FIG. 1;

FIG. 3 is a further perspective view of the head portion of the surgical stapling device of FIG. 1, illustrating a buttress material and a mounting structure separated therefrom;

FIG. 4 is another perspective view of the head portion of the surgical stapling device of FIG. 1, illustrating the buttress material connected to the head portion;

FIG. 5 is cross-sectional view of the head portion and anvil assembly of the surgical stapling device of FIG. 1, as taken through 4-4 of FIG. 5, shown in position between a pair of body lumens;

FIG. 6 is an enlarged view of the indicated area of detail of FIG. 5;

FIG. 7 is a perspective, cross-sectional view, of a fastener according to another embodiment of the present disclosure, for securing the buttress material to the mounting structure;

FIG. 8 is an enlarged view of the indicated area of detail of FIG. 7;

FIG. 9 is an enlarged perspective, cross-sectional view, of a fastener according to another embodiment of the present disclosure, for securing the buttress material to the mounting structure; and

FIG. 10 is a perspective view of the intestinal area of a patient, illustrating a method of positioning the annular surgical stapling device of FIG. 1 to connect the anvil assembly to the tubular body portion.

DETAILED DESCRIPTION OF EMBODIMENTS

Embodiments of the presently disclosed annular surgical stapling device will now be described in detail with reference to the drawing figures wherein like reference numerals identify similar or identical elements. As used herein and as is traditional, the term “distal” refers to that portion which is furthest from the user while the term “proximal” refers to that portion which is closest to the user.

Referring initially to FIGS. 1 and 2, an annular surgical stapling device for use with a buttress material is disclosed herein and is generally designated as 10. Surgical stapling device 10 includes a handle assembly 12 having at least one pivotable actuating handle member 20, and an advancing member 22. Extending from handle member 12, there is provided a tubular body or shaft portion 14 which may be constructed so as to have a curved shape along its length. Body or shaft portion 14 terminates in a staple cartridge head assembly 16. Staple cartridge head assembly 16 is configured to receive a staple guide 60 therein. Staple guide 60 includes at least one annular array of staple receiving slots 62 defined in a distal end thereof and a plurality of staples 70 disposed, one each, in each of staple receiving slots 62. For example, staple guide 60 may include one, two, or more than two annular arrays of staple receiving slots 62. Staple receiving slots 62 are defined in a tissue facing or contacting surface of the distal end of the staple guide 60.

Typically, staple cartridge head assembly 16 includes a staple pusher 53 including a proximal portion having a generally frusto-conical shape and a distal portion defining two concentric rings of peripherally spaced fingers 52, each one of which is received within one of the respective staple receiving slots 62 of staple guide 60.

Additionally, staple cartridge head assembly 16 includes a knife 74, substantially in the form of an open cup with the rim thereof defining a knife edge, disposed within staple cartridge head assembly 16 and mounted to staple pusher 53. The knife edge is disposed radially inward of the pair of annular arrays of staples 71 and the pair of annular rows of staple receiving slots 62. Accordingly, in use, as the staple pusher 53 is advanced, the knife 74 is also advanced axially in a linear direction.

Positioned distally of staple cartridge head assembly 16 there is provided, as seen in FIGS. 1 and 5, an anvil assembly 30 including an anvil member 32 and a shaft 34 operatively associated therewith for removably connecting anvil assembly 30 to a distal end portion of stapling device 10. Shaft 34 of anvil assembly 30 is connectable to a central shaft 22 of stapling device 10 extending through staple cartridge head assembly 16 and connecting anvil assembly 30 to staple cartridge head assembly 16 of surgical instrument 10.

Reference may be made to U.S. Pat. No. 8,322,590 to Patel et al., the entire contents of which are incorporated herein by reference, for a detailed discussion of the construction and operation of annular stapling device 10.

Referring now to FIGS. 2-6, a buttress material 100 and a mounting structure 120 together form an assembly for connecting buttress material 100 to staple cartridge head assembly 16 is shown and will be described. Buttress material 100 is generally annular in shape and includes an annular inner attachment portion 102; an annular middle staple engaging portion 104, disposed radially outward of inner portion 102; and an annular outer portion 106, disposed radially outward of middle portion 104. A substantially centrally located aperture 108, defined by an inner circumference of inner portion 102 is formed through or within buttress material 100. Buttress material 100 may be any shape sufficient to provide support for anastomosis of tissue after surgical stapling device 10 has been fired including, for example, a rectangle, an oval, a triangle or any other polygonal or other shape.

As illustrated in FIGS. 3-6, buttress material 100 is sized such that when buttress material 100 is positioned over the tissue contacting or facing surface of staple guide 60, outer portion 106 of buttress material 100 is substantially axially aligned with an outer surface of staple cartridge head assembly 16, and annular middle staple engaging portion 104 of buttress material 100 overlies staple retaining slots 62 of staple guide 60. Aperture 108 of buttress material 100 is sized to at least receive shaft 22 of anvil assembly 30 and central shaft 22 of surgical stapling device 10 therethrough. It is also contemplated that buttress material 100 may extend radially beyond an inner surface and the outer surface of staple guide 60.

Buttress material 100 may be fabricated from surgical grade, biocompatible, non-absorbable material (i.e. permanent) or absorbable material (i.e. non-permanent), such as a mesh or other porous or non-porous material desirably optionally containing, impregnated, or coated with an adhesive, sealant and/or other medicament. It is also contemplated that each one or more portions of the buttress may be a composite of include both a non-absorbable and an absorbable material. Suitable materials for the fabrication of buttress material 100 and suitable adhesives, sealants, and/or medicaments for impregnation in or application to buttress material 100 may be found, for example, in U.S. Pat. No. 7,942,890, referenced above.

Buttress material 100 may be secured to staple head assembly 16 through the use of one or more fasteners or sutures 140 stitched to mounting structure 120, as illustrated in FIGS. 2-6. Generally, each suture 140 includes a first end or leg 140 a, a second end or leg 140 b, and a body or bridge portion 140 c extending between and interconnecting the first and second ends 140 a, 140 b, as will be described in the embodiments to follow.

Similar to buttress material 100, sutures 140 may be fabricated from surgical grade, biocompatible, non-absorbable material (i.e. permanent) or absorbable material (i.e. non-permanent) or material desirably impregnated with an adhesive, sealant and/or other medicament. It is also contemplated that sutures 140 may be a composite of both a non-absorbable and an absorbable material. Suitable materials of sutures 140 are described above with reference to buttress material 100 and may be found, for example, in U.S. Pat. No. 7,942,890, referenced above.

As mentioned above, sutures 140 function to secure buttress material 100 to mounting structure 120. Specifically, each of first and second ends 140 a, 140 b of sutures 140 may extend through buttress material 100 and extend through mounting structure 120 and may be secured in place to one another through the use of knotting, fusing, heat welding, staking or other similar methods which will limit or prevent first and second ends 140 a, 140 b of sutures 140 from being withdrawn through or from mounting structure 120. It is contemplated that bridge portion 140 c of sutures 140 may rest against a tissue facing or contacting surface of buttress material 100 or against mounting structure 120.

While first and second ends 140 a, 140 b of sutures 140 are shown and described as extending through mounting structure 120, it is contemplated that first and second ends 140 a, 140 b of sutures 140 may extend around mounting structure 140 and tie buttress material 100 to mounting structure 120.

As seen in FIGS. 2-6, mounting structure 120 is in the form of a ring that is dimensioned to fit within a circumference of the inner wall 60 a of staple guide 60 of staple cartridge head assembly 16, in a press fit manner. In an embodiment, ring 120 is formed from an elastomeric material and has a diameter so as to establish a degree of friction between ring 120 and inner wall 60 a of staple guide 60 preventing or inhibiting mounting structure 120 from freely falling out of staple cartridge head assembly 16. It is envisioned that ring 120 may have a substantially circular, transverse, cross-sectional profile, or, as shown in FIGS. 2, 5 and 6, may have a rectangular, transverse, cross-sectional profile. As seen in FIGS. 5 and 6, ring 120 may define a chamfered corner 120 a along an outer and proximal edge thereof. In this manner, the knife edge of knife 74 may first enter into the chamfered corner 120 a of ring 120 upon firing and thus reduce any tendency of ring 120 to interfere or obstruct the firing of surgical stapling device 10.

Being that ring 120 frictionally engages inner wall 60 a of staple guide 60, with buttress material 100 stitched to ring 120 by sutures 140, when ring 120 is situated in staple guide 60, buttress material 100 overlies staple retaining slots 62 of staple guide 60. Specifically, sutures 140 are used to secure annular inner attachment portion 102 of buttress material 100 to ring 120, and annular middle staple engaging portion 104 of buttress material 100 overlies staple retaining slots 62 of staple guide 60.

In use, when surgical stapling device 10 is fired, and staple pusher 53 and knife 74 are advanced, staple pusher 53 expels staples 70 from staple retaining slots 62 of staple guide 60 and into buttress material 100, and knife 74 severs buttress material 100 between annular inner attachment portion 102 and annular middle staple engaging portion 104. By severing buttress material 100 between annular inner attachment portion 102 and annular middle staple engaging portion 104, inner attachment portion 102 may be removed from the surgical site together with surgical stapling device 10, and annular middle staple engaging portion 104 (together with outer portion 106) is secured to the underlying tissue by staples 70.

Turning now to FIGS. 7 and 8, a fastener for securing buttress material 100 to mounting structure 120, according to another embodiment of the present disclosure, is generally designated as 240. Fastener 240 includes a ring-like body or frame portion 242 having a radial dimension so as to overlie annular inner attachment portion 102 of buttress material 100. Fastener 240 further includes a plurality of barbed pins 244 extending from frame portion 242, in a direction parallel to a central axis “A” of frame portion 242, and in a proximal direction from frame portion 242.

In use, barbed pins 244 penetrate through buttress material 100 and penetrate into or are potted into elastomeric mounting structure 120 to thereby hold buttress material 100 in place relative to mounting structure 120.

Turning now to FIG. 9, a fastener for securing buttress material 100 to mounting structure 120, according to yet another embodiment of the present disclosure, is generally designated as 340. Fastener 340 includes a pin or stem 344 integrally formed with and extending from mounting structure 120. Pins 344 extend from mounting structure 120 in a direction parallel to a central axis of mounting structure 120, and in a distal direction from mounting structure 120. Each pin 344 terminated in a mushroomed head portion 346 that is configured and dimensioned to pass through an aperture, slit or the like formed in buttress material 100, specifically, formed in annular inner attachment portion 102 of buttress material 100.

In use, head portion 346 of fastener 340 extends through buttress material 100 to thereby hold buttress material 100 in place relative to mounting structure 120.

Turning now to FIG. 10, there is illustrated the use of annular surgical stapling device 10 and detachable anvil assembly 30 in an anastomosis procedure to effect joining of adjacent intestinal sections “T1 and T2”. The anastomosis procedure is typically performed using minimally invasive surgical techniques including laparoscopic means and instrumentation. At the point in the procedure shown in FIG. 10, a diseased intestinal section has been previously removed, anvil assembly 30 has been applied to the operative site either through a surgical incision or transanally and positioned within intestinal section “T2”, and staple cartridge head assembly 16 of surgical stapling device 10 has been inserted transanally into intestinal section “T1”. Intestinal sections “T1 and T2” are also shown temporarily secured about their respective components (e.g., shaft 34 of anvil assembly 30, and the central shaft 22 of staple cartridge head assembly 16 of surgical stapling device 10 by a purse-string suture or the like).

According to one method, with reference to FIG. 10, buttress material 100 may be positioned and secured to the tissue contacting or facing surface of staple guide 60 of staple cartridge head assembly 16 using any of the mounting structures 120 described above. It is envisioned that staple cartridge head assembly 16 and/or surgical stapling device 10 may come with buttress material 100 pre-positioned and secured to the tissue contacting or facing surface of staple guide 60 of staple cartridge head assembly 16. Alternatively the surgeon may secure buttress material 100 to the tissue contacting or facing surface of staple guide 60 of staple cartridge head assembly 16 prior to use.

With buttress material 100 secured in place, the surgeon maneuvers anvil assembly 30 until the proximal end of shaft 34 is inserted into the central shaft 22 of staple cartridge head assembly 16 of surgical stapling device 10. Central shaft 22 is now engaged to shaft 34 with intestinal sections “T1 and T2” disposed between anvil assembly 30 and staple cartridge head assembly 16. As seen in FIGS. 5 and 10, for example, buttress material 100 is disposed between head assembly 16 and intestinal section “T1”.

Anvil assembly 30 and staple cartridge head assembly 16 are then approximated to approximate intestinal sections “T1 and T2”. Surgical stapling device 10 is then fired to staple buttress material 100 and intestinal sections “T1 and T2” together, and the knife 74 is actuated to cut the portion of tissue and any portion of buttress material 100 (i.e., inner portion 102), to complete the anastomosis. Once anastomosis is complete anvil assembly 30 and staple cartridge head assembly 16 are unapproximated to release intestinal sections “T1 and T2” and buttress material 100 sandwiched therebetween.

In accordance with the present disclosure, it is envisioned that surgical stapling device 10 may be modified for use with a powered actuation assembly. Commonly owned U.S. Pat. No. 8,806,973, the content of which is incorporated by reference herein in its entirety, discloses a surgical device having a powered actuator assembly including powered drive members.

Although the illustrative embodiments of the present disclosure have been described herein with reference to the accompanying drawings, the above description, disclosure, and figures should not be construed as limiting, but merely as exemplifications of particular embodiments. It is to be understood, therefore, that the disclosure is not limited to the precise embodiments described herein, and that various other changes and modifications may be effected by one skilled in the art without departing from the scope or spirit of the present disclosure. 

What is claimed is:
 1. A surgical stapling device for joining tissue portions, comprising: a cartridge assembly including: a staple guide configured to releasably receive a surgical staple; and a knife disposed within the cartridge assembly and configured to axially translate therethrough; an anvil assembly mounted at a distal portion of the cartridge assembly, the anvil assembly configured to move relative to the cartridge assembly between a spaced-apart position and an approximated position; a mounting ring disposed within the cartridge assembly such that the mounting ring is coaxially positioned relative to the staple guide, the mounting ring including a distal portion configured to receive at least one first portion of an annular buttress material; and a ring-like retainer overlying the annular buttress material and concentric with the mounting ring, wherein the ring-like retainer is secured to the mounting ring with the annular buttress material interposed therebetween.
 2. The surgical stapling device according to claim 1, wherein the ring-like retainer includes at least a pair of barbed pins projecting from a proximal surface thereof, extending through the annular buttress material, and potted into the mounting ring.
 3. The surgical stapling device according to claim 2, wherein the at least a pair of barbed pins includes an annular array of barbed pins.
 4. The surgical stapling device according to claim 2, wherein the ring-like retainer defines an inner diameter that is larger than an inner diameter of the annular buttress material.
 5. The surgical stapling device according to claim 4, wherein the mounting ring defines an inner diameter that is larger than the inner diameter of the annular buttress material.
 6. The surgical stapling device according to claim 5, wherein the inner diameter of the ring-like retainer is larger than the inner diameter of the mounting ring.
 7. The surgical stapling device according to claim 6, wherein the ring-like retainer defines an outer diameter that is smaller than an outer inner diameter of the mounting ring.
 8. The surgical stapling device according to claim 1, further comprising: a central shaft extending through the cartridge assembly, wherein the anvil assembly includes an anvil shaft configured to removably connect the anvil assembly to a distal portion of the central shaft extending through the cartridge assembly.
 9. The surgical stapling device according to claim 1, wherein the staple guide includes an annular array of staple receiving slots and the knife includes a knife edge disposed radially inward of the annular array of staple receiving slots.
 10. The surgical stapling device according to claim 9, wherein the staple guide includes a tissue facing surface configured to receive at least one second portion of the annular buttress material such that the at least one second portion of the annular buttress material extends radially outward beyond the annular array of staple receiving slots and the at least one first portion of the annular buttress material extends radially inward across the distal portion of the mounting ring.
 11. The surgical stapling device according to claim 9, wherein the mounting ring includes a proximal portion having a chamfered edge, wherein the chamfered edge of the mounting ring is positioned to facilitate axial translation of the knife distally beyond the mounting ring.
 12. The surgical stapling device according to claim 11, wherein the mounting ring is chamfered along an outer corner thereof.
 13. The surgical stapling device according to claim 12, wherein the chamfered corner of the mounting ring is disposed radially inward of the knife edge of the knife.
 14. The surgical stapling device according to claim 11, wherein the knife edge of the knife is disposed radially between the annular array of staple receiving slots of the staple guide and the chamfered edge of the mounting ring.
 15. The surgical stapling device according to claim 1, wherein the staple guide includes a radial inner surface and the mounting ring includes an outer diameter configured to frictionally engage the radial inner surface of the staple guide when the mounting ring is coaxially positioned relative to the staple guide.
 16. The surgical stapling device according to claim 1, wherein the mounting ring is formed of an elastomeric material.
 17. The surgical stapling device according to claim 1, further comprising: a handle assembly; and a tubular body supported on a distal end portion of the handle assembly, wherein the cartridge assembly is mounted on a distal end portion of the tubular body.
 18. A surgical stapling device for joining tissue portions, comprising: a cartridge assembly including: a staple guide configured to releasably receive a surgical staple, the staple guide defining an inner annular wall having a diameter; and a knife disposed within the cartridge assembly and configured to axially translate therethrough; an anvil assembly mounted at a distal portion of the cartridge assembly, the anvil assembly configured to move relative to the cartridge assembly between a spaced-apart position and an approximated position; a mounting ring disposed within the cartridge assembly such that the mounting ring is coaxially positioned relative to the staple guide, the mounting ring having a diameter greater than the diameter of the inner annular wall of the staple guide, wherein the mounting ring is frictionally secured within the staple guide; an annular buttress material overlying at least a portion of the cartridge assembly and the mounting ring; and a ring-like retainer overlying and concentric with the mounting ring, wherein the ring-like retainer is secured to the mounting ring with the annular buttress material interposed therebetween.
 19. The surgical stapling device according to claim 18, wherein the ring-like retainer includes at least a pair of barbed pins projecting from a proximal surface thereof, extending through the annular buttress material, and potted into the mounting ring.
 20. The surgical stapling device according to claim 19, wherein the mounting ring is formed of an elastomeric material. 